The invention relates to an injection hose for forming construction joints in concrete structures, and having an essentially liquid-impermeable base structure of flexible material, such as rubber or synthetic material, and defining a passage duct, radial openings along the length of the base structure for the escape of injection liquid, at least one longitudinal depression in the area of the radial openings for receiving a strip of a material which is compressible under the pressure of the injection liquid and which covers the openings, and a hose of liquid-permeable material which sheathes the base structure and the strip.
West German Pat. No. 31 03 041 teaches an injection hose having an inner support body comprising a liquid-permeable wall, a first lattice-like, liquid-permeable hose sheathing this support body and a second lattice-like, liquid-permeable hose sheathing this first hose, in which there is provided between the two lattice-like hoses a hose-shaped nonwoven fabric, which is impermeable to concrete particles from the outside to the inside, but which is permeable to sealants from the inside to the outside. Such injection hoses are expensive to produce and not always reliable during use, because of the need to match the lattice-like hoses and the hose-like nonwoven fabric to the concrete particles and to the sealant used. Moreover, such injection hoses of known construction are frequently difficult to install due to their excessive stiffness and can easily be damaged during harsh treatment at the construction site, which prevents a unfirom distribution of the injection liquid throughout the length of the injection hose.
In order to overcome the above disadvantages, West German Utility Model No. 84 25 518.8 teaches an injection hose of the type described in the introduction, in which the radial opening for the escape of the injection liquid is formed as a slit extending throughout the length of the base structure, and in which the edges of the strip are rounded off and received in appropriate side pits of the depression, and the strip has a spring which engages in the slit. This proposal does eliminate the disadvantages of the injection hose known from West German Pat. No. 31 03 041, but it is subject to further improvements.